The big news in a study commissioned by the Washington State Liquor Control Board is that marijuana use in the state is — this year — somewhere in the neighborhood of 175 metric tons. (One metric ton is 2,205 pounds; so, 385,875 pounds, or about 6.2 million ounces, or just over 175 million grams.)

The numbers RAND came up with for marijuana use were achieved through data research and a customized online questionnaire. The amount, new to us, is more than twice what the Office of Financial Management thought the marijuana market in Washington was just before the 2012 election (during which I-502 was voted into law).

But it wasn’t a surprise to the Liquor Control Board … you know, they’ve been racing along, setting up one of two legal marijuana markets known to humans in the modern era.

“The RAND study is an update of earlier information provided by BOTEC/RAND. Our 165 (metric ton) market estimate is in the ballpark of the 175 tons median in the RAND study. We won’t make an immediate change in policy based on the new numbers,” officials at the liquor board said in an email. “We did not use the OFM fiscal analysis as our guide.”

We’ll dissect Washington’s pot habits more — where Washingtonians get their marijuana and more — in another story and will provide a link to it here on Wednesday.

Here are some key findings in the report:

The National Survey on Drug Use and Health (NSDUH) reports that for 2010 and 2011 the average number of individuals in Washington who used marijuana or hashish in the previous month was 556,000, with a 95-percent-confidence range of 475,000–650,000. NSDUH excludes some populations from its sampling frame and self-report surveys typically underestimate consumption. Further, marijuana use has generally been rising, and these figures represent use in 2010 and 2011, not 2013. Thus, the unadjusted figures from the 2010/2011 NSDUH likely understates the number of past-month users in 2013.

Three counties account for about 50 percent of marijuana users in Washington. King County accounts for about 30 percent, while Snohomish and Pierce counties have roughly 11 percent each.

The literature is surprisingly thin concerning how much marijuana users consume during a typical day. That knowledge deficit becomes all the more acute when focusing on a particular jurisdiction and time, such as Washington in 2013. The emphasis has traditionally been on counting users, not counting grams. However, by augmenting that thin literature with data from the web-based consumption survey described above, we estimate that Washington residents who use marijuana 21 or more times per month consume, on average, 1.3–1.9 grams during a typical use-day.

Marijuana consumption in Washington in 2013 is larger than the 85 (metric tons) previously projected by Washington’s OFM. Even before adjusting for survey undercounting/misreporting, our estimates suggest a 90-percent-confidence interval of approximately 120–175 MT. The difference is largely driven by our use of more recent data.

It is difficult to know by how much surveys understate actual consumption. Many of the relevant studies were published more than a decade ago and times have changed; the NSDUH methodology has been improved substantially, and a national increase in marijuana use over the 2000s may have increased willingness to self-report. It is also unclear how national and regional studies are applicable to Washington state. After reviewing the evidence and attempting to adjust for undercounting/misreporting, results from our simulation suggest consumption likely falls within the interval of 135–225 MT, with a median estimate close to 175 MT.

Multiple datasets provide information about the potency of the marijuana consumed in Washington. None is ideal, and there is no way to take a random sample of the universe of marijuana that is sold or consumed. But the available information suggests that lower-potency forms account for a modest share of the Washington market and probably a smaller share than nationwide. (In other words, Washington pot is high potency.)

Here’s the RAND news release:

Marijuana consumption in Washington state is about twice as large as previously estimated, according to a new RAND Corporation study.

Using federal data and information from a new survey of marijuana users in Washington state, researchers say marijuana consumption likely will range from 135 metric tons to 225 metric tons during 2013, with 175 metric tons as the median estimate.

The analysis was done as a part of efforts to help the Washington State Liquor Control Board prepare for commercial sales of marijuana, which will begin in 2014 as a result of Washington’s Initiative 502 that legalized the commercial production and sales of marijuana for recreational use.

The Washington Office of Financial Management previously had estimated that marijuana consumption in Washington would be 85 metric tons in 2013. That estimate was based on federal data from 2008 and 2009, which estimated there were 363,000 past-month marijuana users in Washington. The figure for 2010 and 2011 was 556,000.

RAND researchers say understanding the size and composition of the current marijuana market is important to help state policymakers make decisions about the number of marijuana sales licenses to issue, to accurately project tax revenues and provide a foundation for evaluations of the state’s legalization of recreational marijuana.

“Updated federal data and information we collected from marijuana users in Washington prompted us to conclude that consumption is significantly larger than previously estimated,” said Beau Kilmer, the study’s lead author and a senior policy researcher at RAND, a nonprofit research organization. “There is still a lot of uncertainty surrounding marijuana market estimates, but our work used new insights and novel data collection tools to improve upon previous efforts.”

Randy Simmons, the Initiative 502 implementation project manager with the Washington State Liquor Control Board, said researchers shared their insights about marijuana consumption in June and the information was “very useful” as state officials made decisions about production and licenses.

The Washington state marijuana consumption estimates were compiled using information from the federal National Survey on Drug Use and Health, as well as a web-based survey of marijuana users in Washington state compiled by the research team. The online survey included novel approaches such as showing participants photos of marijuana to help them better report the actual quantity that they use.

“The federal National Survey on Drug Use and Health provides useful information about marijuana users, but it does not account for all of them,” said Jonathan Caulkins, a study co-author and the Stever Professor of Operations Research and Public Policy at Carnegie Mellon University. “We devoted serious attention to this undercounting issue in the report.”

The RAND report estimates marijuana consumption in each of Washington’s 39 counties, showing that the state’s three most-populous counties (King, Snohomish and Pierce) account for about half of all use.

Support for the study was provided by the state of Washington as part of a contract with BOTEC Analysis Corporation, which advised the state on technical issues related to implementation of legal marijuana in the state.

Voters in Washington approved Initiative 502 in November 2012 that legalized recreational use of marijuana for those aged 21 and older, and requires the state to regulate and tax a new marijuana market. Commercial marijuana stores and associated supply chains are scheduled to begin operating in 2014.

The RAND report, “Before the Grand Opening: Measuring Washington State’s Marijuana Market in the Last Year Before Legalized Commercial Sales,” is available at www.rand.org. Other authors of the report are Jonathan P. Caulkins and Linden Dahlkemper of Carnegie Mellon University, Greg Midgette and Rosalie Liccardo Pacula of RAND, and Robert J. MacCoun of UC Berkeley.

Since 1989, the RAND Drug Policy Research Center has conducted research to help policymakers in the United States and throughout the world address issues involving alcohol and other drugs. In doing so, the center brings an objective and data-driven perspective to an often emotional and fractious policy arena.

Bans, moratoriums and zoning regs county by county, as we have them so far: